The Collaborative International Dictionary of English v.0.48:

Monogamian \Mon`o*ga"mi*an\, Monogamic \Mon`o*gam"ic\, a. [See
   Monogamous.]
   1. Pertaining to, or involving, monogamy.
      [1913 Webster]

   2. (Bot.) Of or pertaining to the Monogamia; having a
      simple flower with united anthers.
      [1913 Webster]